In recent years, a wireless communication network referred to as a heterogeneous network (HetNet) has been known. As disclosed in Patent Document 1 (Japanese Unexamined Patent Application, First Publication No. 2012-34048), a configuration example of HetNet is illustrated in FIG. 5. In FIG. 5, a macro cell 101 uses a relatively low frequency band and the coverage (a range in which communication service can be provided) of the macro cell 101 is wide. A small cell 201 is disposed to overlap the macro cell 101 and uses a relatively high frequency band and the coverage of the small cell 201 is narrow.
When the macro cell 101 and the small cell 201 use different frequency bands, a radio terminal apparatus (user equipment (UE)) 300 of a user switches a base station to be connected by performing a handover between different bands, between a radio base station apparatus (hereinafter referred to as a macro cell base station) 100 of the macro cell 101 and a radio base station apparatus (hereinafter referred to as a small cell base station) 200 of a small cell 201. Here, for example, when the UE 300 connected to the macro cell base station 100 using a frequency band fm performs the handover between the different bands to the small cell base station 200 using a frequency band fs, the UE 300 measures a radio signal in the frequency band fs so as to find the small cell 201 for which the handover is possible. In the measurement of the radio signal, the UE 300 switches the frequency band to be used from fm to fs in a measurement period referred to as a measurement gap (for example, see Patent Document 1).
In addition, in Non-Patent Document 1 (3GPP, TS 36.133), a measurement gap is disclosed in a wireless communication scheme referred to as long term evolution (LTE) which is being standardized in the 3rd generation partnership project (3GPP). As an example of the quality measurement instruction, content of a quality measurement instruction of a different band is disclosed in Non-Patent Document 2 (3GPP, TS 36.331). In Non-Patent Document 2, as the quality measurement instruction of the different band, notifying the UE 300 of quality measurement parameters such as a frequency to be measured, a report type (periodic or event trigger), and a measurement gap and information such as a cell individual offset (CIO) and “time-to-trigger (TTT)” necessary for a transmission determination process in a quality measurement result report (measurement report) from the UE 300 to the macro cell base station 100 is disclosed.